Lake Travis flood forecast
How floods actually reach the lake, and whether an event is active right now.
Where the water comes from
Lake Travis floods arrive from upstream, not from the sky over the lake. The big feeders are the Llano River (about 4,200 square miles of Hill Country) and the Pedernales River (about 1,300), plus Sandy Creek and the local creeks around the lake. Rain over the country above Lake Buchanan lands in Buchanan first, which absorbs part of it before anything passes down the chain of lakes.
How much warning there is
River water travels at a measurable pace, so a flood announces itself hours to days ahead. A rise on the Pedernales takes roughly half a day to move from Fredericksburg past Johnson City into the lake. The Llano is slower: a wave that passes Junction typically needs a day to a day and a half to reach Lake Travis. That is why river gauges upstream are the early warning: by the time the lake itself moves, the water has been on its way for many hours.
What the dam does
Lake Travis is the flood control lake of the Highland Lakes. The space above the 681 foot full pool is reserved flood storage, and LCRA operates Mansfield Dam's floodgates to pass stored water downstream on its own schedule. A flood event on this page means the lake is taking on significant water, whatever the gates are doing.
The forecast itself is the members' part.
Members see the 7 day projection with its confidence band, which ramps and closures the water will touch, and custom alerts for the level that matters to them.
No charge if you cancel before the trial ends.
More Lake Travis answers
One email when a flood event or closure starts on Lake Travis. No card, unsubscribe any time.